Vulnerability · Published Nov 5, 2026 · Assigned by redhat
CVE-2026-121997Gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via qtdpsrc declared/actual length mismatch
High 8.1
In plain English
A high-severity heap buffer overflow in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities).
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.7%top 46.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A heap buffer overflow in gdbserver's QTDPsrc packet handler allows an unauthenticated remote attacker to achieve native code execution in the gdbserver process. The vulnerability results from a mismatch between a packet's declared source length and the actual data length, causing hex2bin to write beyond the allocated heap buffer.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | gdb | no fix listed | DEBIAN-CVE-2026-121997 |
| Debian:13 | gdb | no fix listed | DEBIAN-CVE-2026-121997 |
| Debian:14 | gdb | no fix listed | DEBIAN-CVE-2026-121997 |
| Ubuntu:22.04:LTS | gdb | no fix listed | UBUNTU-CVE-2026-121997 |
| Ubuntu:24.04:LTS | gdb | no fix listed | UBUNTU-CVE-2026-121997 |
| Ubuntu:26.04:LTS | gdb | no fix listed | UBUNTU-CVE-2026-121997 |
| Ubuntu:26.10 | gdb | no fix listed | UBUNTU-CVE-2026-121997 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 6 | see references |
| Red Hat | Red Hat Enterprise Linux 7 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Hardened Images | see references |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://access.redhat.com/security/cve/CVE-2026-121997 vdb-entry, x_refsource_REDHAT
- RHBZ#2565679 issue-tracking, x_refsource_REDHAT